Antiplatelets | Notion

Examples include:

Mechanism of ADP receptor inhibitors

Adenosine diphosphate (ADP) is one of the main platelet activation factors, mediated by G-coupled receptors P2Y1 and P2Y12.
The main target of ADP receptor inhibition is the P2Y12 receptor, as it is the one which leads to sustained platelet aggregation and stabilisation of the platelet plaque.

Evidence

As aspirin and ADP inhibitors work by blocking different platelet aggregation pathways, their potential synergy has been studied by multiple clinical trials, particularly in high-risk patients presenting with acute coronary syndrome (ACS) or undergoing percutaneous coronary intervention (PCI).
Clopidogrel used to be the most commonly used ADP inhibitor, however, due to its interindividual variability in antiplatelet effects, newer agents such as prasugrel and ticagrelor have been developed.
Multiple trials since have shown a marked reduction in short- and long-term ischaemic events when using prasugrel and aspirin, compared to clopidogrel and aspirin in moderate- to high-risk ACS patients.
Current NICE guidelines for ACS, therefore, recommend starting dual antiplatelet treatment (DAPT) with Aspirin (75mg daily) and Ticagrelor (90mg twice daily) for 12 months, as a secondary prevention strategy.
NICE guidelines for people with ACS undergoing PCI recommend aspirin (75-100mg daily) in combination with either prasugrel (10mg daily), ticagrelor (90mg twice daily), or clopidogrel (75mg daily, if prasugrel or ticagrelor are not suitable) for 12 months, with aspirin alone thereafter.

Notable adverse effects

Interactions and contraindications

A drug interaction exists between clopidogrel and proton pump inhibitors, particularly omeprazole and esomeprazole, leading to reducing antiplatelet effects.
Patients with prior stroke or transient ischaemic attack, high risk of bleeding, and prasugrel hypersensitivity are absolute contraindications to prasugrel use.